## Amazon Interview Question for SDE1s

Country: United States

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2
of 2 vote

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SOLUTION:

``````import java.util.List;
import java.util.Map;
import java.util.HashMap;
class TreeNode {
int val;
List<TreeNode> kids;
}
public class HouseRobTree {
public int houseRob(TreeNode root) {
Map<TreeNode, Integer> money_in_tree = new HashMap<>();
return houseRobHelper(root, money_in_tree);
}

private int houseRobHelper(TreeNode root, Map<TreeNode, Integer> money_in_tree) {
if(root == null) return 0;
if(root.kids == null || root.kids.isEmpty()) return root.val;
if(money_in_tree.containsKey(root)) return money_in_tree.get(root);

int max = 0;
for(TreeNode kid: root.kids) {
max = Math.max(max, houseRobHelper(kid, money_in_tree));
if(kid.kids != null) {
for(TreeNode grandKid: kid.kids) {
max = Math.max(max, houseRobHelper(grandKid, money_in_tree) + root.val);
}
}
}
money_in_tree.put(root, max);
return max;
}
}``````

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0
of 0 vote

I think this would be easier... Note: don forget to write code to populate the tree

``````import java.util.List;

public class RobNTree
{

static int max;

static class TreeNode
{
int val;
List<TreeNode> kids;
}

public static void main(String[] args)
{
max = 0;
TreeNode root = null;
// populate tree
if (root != null)
traverse(root, 0);

System.out.println("The max possible loot is " + max);
}

private static void traverse(TreeNode node, int sum)
{
sum += node.val;
if (node.kids.isEmpty())
max = (sum > max) ? sum : max;
else
for (int i = 0; i < node.kids.size(); i++)
traverse(node.kids.get(i), sum);
}

}``````

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0
of 0 vote

this wont give right answer. Question says two directly linked houses/nodes can't be broken on same night. Meaning we cant add values of 2nodes in sum if they are connected. Node and its kid node is directly connected.

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0
of 0 vote

Howdy Mate,

Amazon Interview Question for SDE1s being contrived to exist for many projects simply so it can be run will be the first to hit the wall, but those projects where the functions to make existing transactions cheaper in real world applications will find the elusive real world demand.

I recently attended the AWS Summit London 2018. During the afternoon session about "Open Source at AWS" there were some resources mentioned for persuading your company that open source can be a great benefit to them.
Unfortunately this wasn't one of the slide sets which has been made available after the event.

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Cheers,

Name:

Writing Code? Surround your code with {{{ and }}} to preserve whitespace.

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